Lighting on helmets is not new. U.S. Pat. No. 4,195,328 shows an early lighting system providing for an auxiliary headlight to be mounted on a safety helmet 26. The light utilizes a halogen quartz lamp 124 with a reflector 126. In order to address heating concerns, slots 114,118 with a perforated lens cover 116 so as to “permit a dissipation of any internal heat from lighting elements.” Such a heat removal system would probably work for halogen lighting but would not be expected to satisfactory remove heat from a high power LED. Other lighted helmet constructions include U.S. Patent Application Nos. 2008/0080171, 2008/0170382, 2008/026638 and 2005/0265015.
U.S. Pat. No. 5,871,271 discusses the use of a ten candle power LED as a headlight which would appear to be a low power LED. A common conversion in the green light spectrum is believed to be 680 lumens per watt. 12.7 lumens are a candle power. A conversion of ten candle power to watts provides what appears to be a LED having a maximum output wattage of approximately 0.2 watts. High power LEDs are commonly provided today are at least one, if not five or ten watts. A principal difference between high and low power LED is that a low power LED may provide sufficient lighting so that a rider might have increased visibility for safety concerns, while a high power LED would be much better suited for use as a headlight to illuminate a source at a distance. The headlight of the '271 Patent is not expected to provide significant illumination at a distance.
Even though U.S. Pat. No. 5,871,271 discloses the use of a ten candle power LED: “the headlight or reading function can be enhanced by using high brightness LEDs such as the 10 candlepower white LEDs manufactured by Toshiba corporation,” high power LEDs were not a viable commercial option when that application was filed. Furthermore, based on the construction of placing the LEDs in a recess of the hard shell outer layer and not providing any separate heat removal capability as is shown in FIGS. 2, 3a and 3b, a high power LED substituted for a low power LED in that construction would result in burn out almost instantaneously due to the heat buildup and absence of a heat sink (low power LEDs do not normally require a heat sink of any significant size). The '271 Patent is believed to show the use of lights on bicycle helmets principally for the use of identifying the rider as opposed to illumination as a headlight.
References such as U.S. Pat. No. 6,955,444 show a surgical head light in which high powered LEDs are employed such as a one watt and a five watt LED which explicitly describe the need for a heat sink. There is no room for this bulky heat sink in constructions such as the '271 Patent. The '444 Patent describes a five watt LED requiring a heat sink four times that use for a one watt LED. The applicant and the owner of the '444 Patent have found that when purchasing an LED strong enough to provide headlights which can be clamped on to the head of the user such as on the helmet, that the heat sinks are heavy and bulky and thus “contribute[s] to discomfort for the wearer of the head mounted lamp” (Column 1, lines 45-48). In order to overcome the discomfort of heat sinks for high powered LEDs at five watts, this owner of the '444 Patent used three watt LEDs so that smaller heat sinks could be employed with such constructions than would otherwise be required for higher wattage bulbs.
Of course, references are available directed to various LED heat sinks such as U.S. Pat. No. 6,799,864, U.S. Pat. No. 7,040,388, U.S. Pat. Nos. 5,173,839, 7,489,031, 6,827,130 and 6,999,318 and probably others. Similarly, there are patents related to the cooling of helmets such as U.S. Pat. Nos. 6,598,236, 7,219,371, 7,296,304, 7,010,813 and others.
Nevertheless, in spite of the prior art related to the general idea of providing a helmet with LEDs or providing a head lamp for the head of a user, the applicant believes that a lightweight helmet without a separate bulky high power LED heat sink is needed for at least some applications with improvements over the prior art are believed to be necessary in various applications.